The below article was recently published in US publication Swine Outlook - Summer 2016 edition.

In recent years, there has been a push towards the elimination of antibiotic growth promoters (AGP’s) from the food supply chain due to growing concerns over antibiotic resistance. Due to these pressures, producers have started to focus more on the complete animal production system such as feed management, vaccination strategies and biosecurity. As part of this push, much attention has been given to natural and sustainable alternatives to AGP’s that can help deliver the same feed efficiency, growth and disease protection achieved by AGP use (Windish et al., 2008).

The term ‘gut health’ is often used today for both humans and animals. In fact, lifestyle blogs and e-newsletters that promote ‘gut health’ and management of gut diseases, such as irritable bowel syndrome or leaky gut syndrome, are becoming increasingly popular in today’s culture. However, the term ’gut health’ has never been precisely defined in any known scientific manner (Bischoff, 2011). The simplistic view is that gut health refers to the absence of disease, however there are more criteria that can be used to determine the health of the gastrointestinal (GI) system, such as: effective digestion and absorption of ingested nutrients through a well-functioning epithelial barrier, a resilient microbiome population and a good immune status, all of which contribute to overall well-being (Bischoff, 2011).

The epithelium of the GI tract forms a large barrier/interface between the body and the external environment. One of the main functions of the epithelium is nutrient absorption which offers protection through a physical barrier, from pathogens and toxins (Suzuki, 2013). Furthermore, it accommodates the commensal microbiome, which helps prevent pathogenic organisms from colonising and aids in the utilisation of nutrients. There is a constant interaction between the host and microbiota. The relationship is generally symbiotic but in the case of pathogen challenge, the intestinal immune system has different means of protecting the host, such as antibody and cellular responses. All of which can help in minimising the challenge and damage to the GI tract.

The microbiome, epithelial barrier and intestinal immune system are key parameters that affect gut health and a lot of research has been done to determine the effect of AGP alternatives on these functions.

Phytogenics are a group of compounds that have been investigated for their beneficial effects in animal production. It is often forgotten how humans have relied heavily on plants and herbs throughout history for medicinal purposes. To this day, we still find plant derivatives in modern medicine for example, morphine is derived from the poppy plant (Papaver somniferum).

Within the phytogenic group are essential oils (EO), whose phenol constituents show good antimicrobial properties. The EO from oregano has often been studied for its beneficial effects on gut health. Carvacrol and thymol are the main phenol constituents that are found in oreganos essential oil (OEO). In an in-vitro study by Soković et al. (2010), it was concluded that the oil obtained from Oreganum vulgare offered the highest and broadest antimicrobial activity. Once consumed, those compounds can play a role in modulating the intestinal microbial population and aid in the reduction of pathogenic bacteria, such as E. coli.

The antibacterial effects associated with the use of phytogenics can have a very important impact on production. Post-weaning diarrhoea of piglets is often caused by an enterotoxigenic strain of E. coli. With Orego-Stim being able to reduce E. coli in the GI tract (Figure 1), it can be assumed that it would have an effect in minimising the impact of diseases related to GI tract pathogen challenges. Indeed, in a trial conducted in 2009, weaned piglets receiving either 250g or 500g of Orego-Stim per tonne of feed had reduced incidences of post weaning diarrhoea and mortality, as well as improved weight gain and FCR compared to control piglets.

Other work recently conducted by Anpario (unpublished) evaluated the effect of Orego-Stim on the rate of enterocyte production in the intestine by measuring proliferating cell nuclear antigen (PCNA) in the duodenum, jejunum and ileum (of broiler chickens). In all three intestinal sections, it was seen that the PCNA was higher in the Orego-Stim supplemented group, indicating a faster enterocyte generation rate (Figure 2). This increased rate of enterocyte production will help to maintain intestinal architecture (e.g. villus height) and mitigate the damaging effects of gut challenges, such as those associated with weaning for piglets. Maintenance of intestinal structure promotes effective digestion and absorption of nutrients and reduces intestinal disorders, leading to better, more efficient growth.

Figure 2: The rate of enterocyte generation through measurement of PCNA in broilers. Values are means. *Significant difference between groups declared at P<0.05

In the same work, Orego-Stim was shown to increase both phagocytosis by immune cells and the antibody titre to vaccination, demonstrating its ability to positively influence immune responses.

Pig producers strive for increased productivity and seek cost-effective feed additives to help achieve this. Phytogenics and more specifically, essential oils, are becoming increasingly popular within the feed industry. Orego-Stim, based on oregano essential oil, is a consistent product that delivers consistent results. Gut health is recognised as being central to animal health and performance; Orego-Stim has been demonstrated to enhance gut health through favourable changes to immune responses, the intestinal microbiota and gut epithelium.